OPRPs are not that hard to understand. They are just all the points that did not become CCP and are not included in prerequisite programs. We used to call them CPs earlier. They are called General control measures in Dutch HACCP, CPs in IFs and process monitoring in BRC.
Perhaps you can remember that in the earlier days of HACCP, companies used to have over 10 CCPs. Nowadays they only have 2-4 CCPs. The other 6-8s can mostly considered as OPRP.
You have to control them, but not that hard as a CCP.
Sorry I found a question, if we put CP=OPRP, or from hazard analysis (severity multiple likelihood) just we conclude ccp/oprp, the we missed 22000 7.4.4: evaluation of control measures based on mention ed 7 criteria and defined parameters and logic method!